text: Some of the ions' kinetic energy is transferred to the cathode. This happens partially through the ions striking the cathode directly. The primary mechanism, however, is less direct. Ions strike the more numerous neutral gas atoms, transferring a portion of their energy to them. These neutral atoms then strike the cathode. Whichever species (ions or atoms) strike the cathode, collisions within the cathode redistribute this energy resulting in electrons ejected from the cathode. This process is known as secondary electron emission. Once free of the cathode, the electric field accelerates electrons into the bulk of the glow discharge.  Atoms can then be excited by collisions with ions, electrons, or other atoms that have been previously excited by collisions.